Answer:
[tex]z=6[/tex]
Step-by-step explanation:
[tex]-2.8\left(z+1\right)-\left(3.5z-9\right)=-31.6[/tex]
[tex]-6.3z+6.2=-31.6[/tex]
[tex]-6.3z+6.2-6.2=-31.6-6.2[/tex]
[tex]-6.3z=-37.8[/tex]
[tex]\frac{-6.3z}{-6.3}=\frac{-37.8}{-6.3}[/tex]
[tex]z=6[/tex]
